[英]get feature names of SelectKBest function python
我從sklearn實現了SelectKBest,我想得到K最佳col的名稱,而不僅僅是每個col的值。
我需要做什么?
我的代碼:
X_new = SelectKBest(chi2, k=2).fit_transform(X, y)
X_new.shape
X_new是一個numpy.ndarray,它有k col但沒有col名稱。
您可以獲取所選要素的索引 。
例1 :
from sklearn.datasets import load_iris
from sklearn.feature_selection import SelectKBest
from sklearn.feature_selection import chi2
iris = load_iris()
X, y = iris.data, iris.target
selector = SelectKBest(chi2, k=2)
selector.fit(X, y)
X_new = selector.transform(X)
X_new.shape
print(selector.get_support(indices=True))
現在,如果您真的想獲得列的實際名稱,我們需要使用pandas 。
例2 :
from sklearn.datasets import load_iris
from sklearn.feature_selection import SelectKBest
from sklearn.feature_selection import chi2
import pandas as pd
iris = load_iris()
X = pd.DataFrame(iris.data, columns=iris.feature_names)
y = pd.DataFrame(iris.target)
selector = SelectKBest(chi2, k=2)
selector.fit(X, y)
X_new = selector.transform(X)
print(X_new.shape)
X.columns[selector.get_support(indices=True)]
# 1st way to get the list
vector_names = list(X.columns[selector.get_support(indices=True)])
print(vector_names)
#2nd way
X.columns[selector.get_support(indices=True)].tolist()
結果 :
Index([u'petal length (cm)', u'petal width (cm)'], dtype='object')
['petal length (cm)', 'petal width (cm)']
['petal length (cm)', 'petal width (cm)']
model = SelectKBest(f_classif,k = 8).fit(X,Y)
Selected_feature_names = X.columns [model.get_support()]
model=SelectKBest(k=5)
model.fit(X,y)
print(model.get_params)
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